Method for making granules

ABSTRACT

The invention concerns a method for making granules which consists in coating in a turbine a core with at least a coating layer consisting at least of a solution and then in drying the coated core, after each new coating. The invention is characterised in that drying is carried out in the operating turbine and comprises the following phases: mild drying by spraying a lukewarm gas stream corresponding to a temperature between 25° C. and 35° C.; strong drying by spraying a hot gas stream corresponding to a temperature between 40° C. and 50° C.; final drying by spraying a lukewarm gas stream corresponding to a temperature between 25° C. and 35° C. The invention is applicable in particular to granules for aromatic, cosmetic, food or dietetic use.

[0001] The present invention relates to a process for the production ofgranules which can find application particularly for fragrance,cosmetic, foodstuff or dietetic usages.

[0002] In this field, there is already known from WO 97/04861, a processfor the production of solid granules including aromatic, food, dieteticor cosmetic substances.

[0003] This prior process consists: in forming a core serving as asupport, constituted by excipients associated or not with activesubstances, covering the core in three steps with at least one layer,these three steps being carried out for each successive layer by:

[0004] cladding the core with active substances associated or not withexcipients,

[0005] drying the layer,

[0006] screening the covered core.

[0007] The granules obtained by this type of process are particularlyadvantageous and can constitute granules to be chewed, sucked, swallowedor dissolved and can contain vegetable extracts and essential oils (orthe like).

[0008] Although giving good results, the process according to WO97/04861 can be improved, because it lacks productivity.

[0009] The principal problem posed by this prior reference is the timeof production of the granules, which is much too long.

[0010] Thus, the time of screening and drying are long. The saving oftime takes place by decreasing the number of screenings, in the absenceof turbine—drying screen transfers and in dynamic drying of the granulesmuch more rapidly.

[0011] Moreover, the step of drying requires a transfer of the granulesinto an oven which corresponds to a supplemental step which addstransfer time to the overall time of production.

[0012] The present invention permits overcoming the drawbacks of thepresent techniques and provides to this end an improved process.

[0013] In the first place, this process permits considerably shorteningthe time of production of the granules.

[0014] To do this, the invention has the advantage of omitting the stepof transferring to an oven to carry out drying, as well as most of thescreenings.

[0015] To this end, the drying takes place in the same medium as thecladding of the core, in a turbine.

[0016] Moreover, the process here proposed has the advantage of usingdifferent successive steps for drying and which permits optimizing it.

[0017] In particular, complete drying begins when the cladding of thecore has been carried out and this at a moderate temperature.

[0018] Once this fundamental drying has been carried out, a strongerdrying is carried out and then a drop in temperature for a third drying,beneath a heated flow at moderate temperature.

[0019] The use of such drying steps has the advantage of producing aprogressive temperature increase of the granules, which permits avoidingany thermal shock and thus substantially improving the quality ofproduction.

[0020] Another advantage of the invention is that the drying is carriedout in a turbine, which prolongs the cycle of rotating the granules.

[0021] In this way, there is realized an even better sphericity andgranulometric homogeneity of the granules obtained, and the number ofscreenings required is reduced.

[0022] Other objects and advantages will become apparent from thedescription which follows.

[0023] The present invention relates to a process for the production ofgranules, particularly for aromatic, cosmetics, foodstuff or dieteticuse, consisting in cladding in a turbine a core of at least one claddinglayer constituted by at least one solution, then drying the coveredcore, after each new cladding, characterized by the fact that the dryingtakes place in the turbine in operation and comprises the followingphases:

[0024] gentle drying by projection of a warm gas flow corresponding to atemperature between 25° C. and 35° C.;

[0025] strong drying by projection of a hot gas flow corresponding to atemperature between 40° C. and 50° C.;

[0026] terminal drying by projection of a warm gas flow corresponding toa temperature between 25° C. and 35° C.

[0027] This process will comprise, according to preferred modificationsof the invention, the following steps:

[0028] it comprises, after drying, a cooling phase to ambienttemperature;

[0029] the gaseous flow is a flow of purified and filtered air;

[0030] there is used to constitute each cladding layer:

[0031] a binding solution,

[0032] a micronized powder;

[0033] for each cladding layer, the binding solution is sprayed on thecore and there is carried out a pause permitting impregnation of thecore, before depositing the micronized powder;

[0034] there is carried out a screening of the granules only at the endof the operation;

[0035] the core and/or the cladding layers comprise at least one activesubstance.

[0036] The type of granules obtained by the process according to theinvention is not limited and reference can be had to patent applicationWO 97/04861 as to several examples of embodiment and of particularcomposition.

[0037] Generally speaking, the process consists, starting from a basiccore, in providing different superposed cladding layers.

[0038] At least one layer is required, but several layers are generallyprovided.

[0039] As already exists in the prior art, the cladding according to theinvention uses at least one solution.

[0040] Once the core is impregnated by the solution, the deposited layerof solution can be dried in a drying step.

[0041] After drying, there can be carried out if necessary a freshcladding by a new deposit of the solution on the periphery of the core.

[0042] According to the invention, the drying that is used is carriedout in a turbine which is the same as the turbine that served to cladthe core.

[0043] Moreover, the turbine is held in rotation so as to continue themovement of the granules, which optimizes greatly the circulation of thegaseous flow serving for drying.

[0044] As to this, the drying that is used comprises several varyingsteps, particularly according to the temperature of the gas flow whichis projected on the granules.

[0045] In a first instance, a gentle drying is carried out by projectionof a warm gas flow.

[0046] There is meant by the term “warm”, a temperature comprisedbetween 25° C. and 35° C.

[0047] This gentle drying step permits drying throughout the core of thegranule thus coated and ensures progressive increase of the temperatureof the granule.

[0048] In a second step, a stronger drying is carried out by projectionof a hot gas flow.

[0049] The term “hot” means a temperature of the gaseous flow comprisedbetween 40° C. and 50° C.

[0050] This step at higher temperature increases the rapidity of thedrying of the granule.

[0051] In particular, the layer of deposited solution will be morerapidly fixed in this step.

[0052] In a third step, a terminal drying is carried out by projectingagain a warm gas flow, which is to say of a temperature comprisedbetween 25° C. and 35° C.

[0053] For reasons of simplicity, there can be used a flow at the sametemperature as that used for the preliminary gentle drying.

[0054] The terminal drying permits progressively lowering thetemperature of the granules preferably before a cooling step to ambienttemperature.

[0055] This cooling step can be carried out under a flow of air atambient temperature, which is to say substantially about 20° C.

[0056] Preferably, the gaseous flows projected on the granules are airflows.

[0057] When cooling has been achieved, the steps of cladding and dryingcan be repeated as often as necessary.

[0058] The screening of the granules is no longer necessary after eachcladding. Only several screenings, or even a single screening at the endof the operation, is carried out.

[0059] Preferably, the cladding layer used in the present productionprocess is composed of two components in different phases.

[0060] Thus, in addition to the solution that is employed which,according to this modification, will be a solution with bindingproperties, there is used a micronized powder.

[0061] The micronized powder has a supplemental function which is togive quickly a large volume to the granules.

[0062] The micronized powder coacts with the binding solution by beingfixed on this latter.

[0063] Thus, in each cladding layer, the binding solution can be sprayedon the core, then after a possible pause, carry out the deposit of themicronized powder.

[0064] By way of example, the process of production in this case can bepracticed by using a core based on maltitol or else a mixture of sodiumbicarbonate and citrate. It could also be a matter of pollen grains.

[0065] Again by way of example, the binding solution according to theinvention could comprise essential oils, emulgin as well as Luviskol(trademark of BASF). Citric acid could also be present.

[0066] As to the micronized powder, it could also be maltitol.

[0067] Generally speaking, but according to the uses, the core and/orthe layers of cladding (at the level of the micronized powder or thebinding solution) will comprise one or several active substances.

[0068] They could be fluid extracts or essential oils, for example.

[0069] As to the time of drying, the following sample shows the rapidityof the cycle, for production of 5 kg of granules in a test turbine:

[0070] gentle drying: 1 minute at 30° C.

[0071] strong drying: 2 minutes at 45° C.

[0072] terminal drying: 1 minute at 30° C.

[0073] Then, a cooling to ambient temperature of 5 minutes was carriedout.

[0074] The deposition of the cladding layer by impregnation itself tooka time of 5 minutes, after drying.

[0075] In total, the cladding with one layer took 15 minutes instead ofabout 2 hours 30 minutes according to the prior art.

1. Process for the production of granules particularly for fragrance,cosmetic, foodstuff or dietetic use, consisting in cladding in a turbinea core with at least one cladding layer constituted at least by asolution, then drying the covered core, after each new cladding,characterized by the fact that the drying takes place in the turbine inoperation and comprises the following phases: gentle drying byprojection of a warm gas flow corresponding to a temperature between 25°C. and 35° C.; strong drying by projection of a hot gas flowcorresponding to a temperature between 40° C. and 50° C.; terminaldrying by projection of a warm gas flow corresponding to a temperaturebetween 25° C. and 35° C.
 2. Process for the production of granulesaccording to claim 1 characterized by the fact that it comprises, afterdrying, a phase of cooling to ambient temperature.
 3. Process for theproduction of granules according to anyone of claims 1 or 2characterized by the fact that the gas flow is a flow of purified andfiltered air.
 4. Process for the production of granules according to anyone of claims 1 to 3, characterized by the fact that there is used toconstitute each cladding layer: a binding solution; a micronized powder.5. Process for the production of granules according to claim 4,characterized by the fact that for each cladding layer, the bindingsolution is sprayed on the core and there is carried out a pausepermitting the impregnation of the core, before the deposit ofmicronized powder.
 6. Process for the production of granules accordingto any one of claims 1 to 5, characterized by the fact that the coreand/or the cladding layers comprise at least one active substance.